Field-effect transistors are now available that exhibit high-speed operation at low operating voltages and that have a high integration density. In order to more efficiently withstand a short channel effect and provide a higher drive current at low operating voltages as compared to a conventional field-effect transistor, there is a rising interest in fin field effect transistors (FinFET) which have channels that are formed in a three-dimensional structure.
In recent years, in order to improve the performance of the semiconductor device, there has been used a technique in which a layer including a stress material is formed by epitaxial growth to increase the carrier mobility of a channel region of the semiconductor device.